I'm using QGIS. I have a layer made up of many adjacent polygons - let's call them "countries". I currently use the Atlas plugin to export each "country" polygon to a .png file.

I want to further subdivide each polygon into 3 or more sections (let's call them "states"), and to be able to export these in the same way. However, I want my original polygons ("countries") to remain intact (and hence exportable). Furthermore, if I alter my "country" boundaries, I want the "state" boundaries that are affected to also be automatically updated.

From the edit and the comment, what the poster seems to do, is editing geometries with a topology.

Basic GIS modelisation relies on «spaghetti model» which are layers of features, which are independant, with their own geometry.

Another way of doing things is to modelize the geometries using a specific topology : the geometries of the features share a common set of canonical entities, which are shared by features. Usually this is done with a node-edge-face model.

QGis does not currently features real topological geometry edition. But here are some hints if you want to go this way :

PostGIS 2.0 has a new topology feature set. A QGis plugin is
currently developped to support this feature, enabling you to fulfill
your needs. Alpha state for the moment, but check
http://www.postgis.org

semi-topologic editing. There are options in QGIS enabling pseudo-topology when editing geometries : new points of the geometry sit on another feature's shape for example. See «Preferences->snapping options» and the corresponding part in QGIS Manual. This is not full topology editing since modifications to the base geometry are not automatically propagated to the other.

Thanks for the answer. Not sure that is exactly what I want to do, however. I will be defining the polygons for each state myslf. I was considering making each set of states (for a specific country) a separate layer, but then changes in the country layer are not reflected in the states. Is there any way to link the layers? As regards Atlas, I'll look at the issue tracker again. Thanks.
–
SpinnerFeb 18 '12 at 22:06